DC Motor

Electrical Engineering

How It Works

A direct current (DC) motor transforms electrical energy into continuous mechanical rotational torque through the Lorentz force acting on current-carrying rotor conductors immersed in a stator magnetic field. To ensure continuous unidirectional torque, a split-ring commutator and stationary carbon brushes reverse the direction of armature current every 180 degrees of mechanical rotation. As the rotor spins, it simultaneously generates a counter-electromotive force (back-EMF) that opposes the supply voltage and self-regulates motor speed under load.

Governing Equation
T = k_t · Φ · I_a   |   V_t = E_b + I_a · R_a   |   E_b = k_e · Φ · ω